1. Field of the Invention
The present invention relates to brewers, and more particularly, to a brewer capable of making at least a single cup of beverage from fresh, infusible, ground alimentary material, such as coffee.
2. Description of the Prior Art
Heretofore, many attempts have been made to produce a single cup of freshly brewed coffee by percolation. This is particularly relevant in the case of automatic dispensing machines. Examples of prior art brewers include U.S. Pat. No. 3,552,976, King, 1971. The brewer in accordance with King '976 requires a porous support with a continuous band of filter paper passing over the support and an upper reciprocating tube which clamps the filter paper band in place on the support and acts as a receptacle for the coffee grounds and the hot water. A piston in a cylinder below the support draws the water under negative pressure through the filter paper band, and the brewed coffee flows through a spout in the side of the cylinder.
In U.S. Pat. No. 4,852,472, In-Albon et al, 1989, an espresso machine is described in which the ground coffee is first compressed by two pistons in a sliding scalding cylinder, and steam or hot water is passed therethrough at high pressure.
In U.S. Pat. No. 4,506,596, Shigenobu et al, 1985, a continuous filter tape is utilized, similar to King, '976, and a reciprocating cylindrical tube clamps down on the filter tape and porous support thereunder. Water and coffee grounds are poured into the tube, and a piston moves down in the tube to press the water through the grounds and the solution through the filter.
All of the above brewers are capable of brewing a single cup of fresh coffee. However, it has been found that one of the ingredients for obtaining superior brewing of coffee with a short dwell time is to agitate the grounds and water as the coffee is being brewed. In King, '976, the incidence of agitation is relatively minor. Both In-Albon et al, '472, and Shigenobu et al, '596, rely on high pressure infusion to produce a good quality brew. These latter systems are relatively expensive. Furthermore, the use of a filter paper band of the type described in King, '976, and Shigenobu et al, '596, requires frequent and additional maintenance to replace the filter band and to clean the areas surrounding the filter tape path.